SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39376d1f6702031ebdd6522e064bbb8d3c8b81570a71d183e27c4a1314b7d593' 
  AND token = 'TCD1DUQnxTgsD8OnbdhEYcpDmq9O0mqZ2Ie1HUwJ1VY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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