SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd65603b1fa6fc5b69fae69b79310a3a0c60020f895e54de0550920f048c53522' 
  AND token = 'IRhB4RYdBg13+t1jCjJseKfYhc6iXLdEMBRPGFDmC08=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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