SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf86b982f4ac2557aad7d609fab7b6174a7d709a898a062abc743b4a2be11c25' 
  AND token = 'nNBVTYK9kLP3z7cxjm9hLSZZAirtNxdymsFBtjp75mA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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