SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1484f54f2a062d5c2d99182b40be62871c1d8703015bf701c81f4a0eb14eefe' 
  AND token = 'UeEUQ/npD/Ef0JfsvPogtwGmuGyEqHHdXGuxggzeL1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}