SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5004c8a18fa92535c5cf972c407ee46fd5927eea3cac4ebc65fd2c1ab51130e' 
  AND token = 'Ovv5hnCAWUGKOzcQ+cL1DCSd28exKOcrIHr4WMhGNbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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