SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e7304f7b7a9d5165b959479965668e26684641771a5fb383b034b06a94ae5da' 
  AND token = 'BZnDuqjNCEfBzzgE7VZFL+9UwpAfqv5cNSpYUZCYdhc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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