SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '215aee1c38901b79a73d08e9c81442811618f75a2e722c027c4dd17b33129505' 
  AND token = 'LRm1YsLtCrqZhRxOMES+FlsPabnYArLyMSQRH98PXCE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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