SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aaed101688a33ba79beaa98417e7891a645c0dc4f2d5468674db189e544fc3cc' 
  AND token = 'Vrun3+PoJ3WczrhiAfGKUiF7VCOUNLJs/DvDpCfhioM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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