SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d6e102ea6623338d193b6ff1a5783114a865a06ce418af3ced058c4a09f5bd2' 
  AND token = 'dL+sMIWwzynnwWExOy0u4UDjsTRPFR2fY9RlqSmQFmc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}