SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3a3e542da4f0c070997c2bfe69d6140d7dc1080b24ed6fd629d6e113c550509' 
  AND token = 'Q/8HouK7ZYV0TTGWIfEE1x4Nf12MGlCgevyz0fBLQcY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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