SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e5312ed94ad6807478fd590eb1929ba3dfd0659713d20c97044d71fe8bf59bf' 
  AND token = '1NTz+PWEXK72h3Esje1GqEHt2X+Ls5oI4BtITzCTy/E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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