SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85d5f5a890839eaacedd2273ca0b27974f5e2e0789da47527499801238c806c2' 
  AND token = 'qgQamcNYNRhx54knnzScdAFyU8Er2Tbd9KBLIr2hjQ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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