SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2656777c195a19306d7685b79083f02517d0a2c0db15d3987c35f84d394e09d8' 
  AND token = 'NM2I1dJUkuWhvtiPn7GHXOahA3Tn/kve8cUll7xgJmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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