SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be3a163fc3b8eb8c694f0b93a34640e60047d3877b573f055153409d82caee93' 
  AND token = 'PuX4uPK8Q5EuerK8TRfuQfSKW+owAjrbMJK0OkuppkU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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