SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a587578d7ebc27075448a2322f093f6a2cb5219881a72a73d43765f2c4180c7d' 
  AND token = 'AW0emvtjHikk4U7FB7yHUvGtZzYwq96Lg5F+LULaNkQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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