SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1286eeba9a75eb065a1cfb08b933012f2223168215f10c10923afe7c5cc4b4ce' 
  AND token = 'H4uEzgRfeFF5UD9iFWkA9o3ExhqIr2ghYstgiHKyNPc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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