SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86aa4014c7e74ee3443a146f8f8fbc32e60486d64ee4c8f67bb59d85b1d4e70f' 
  AND token = 'Z921qP2F718j/rDzlRHuXsqMeUH+MJK9IeuJrvTOwmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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