SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f9bb4dc155035d32725628f250d8aa6dc9554286062cda528553f0317ed8014' 
  AND token = 'rlQ6vJPn2JoUPYkJByLMh0LRIc2Akqw8lzuON2cLPyA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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