SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2bd184d1501b73d64f830f1549475c045c139dc5c21fc054f457034f303cfe4' 
  AND token = 'yKKy2XORWpLjpLicRJm3yD/rd1M+G5nBU0MGd0wceBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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