SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4817eb19d49fb6a7b27535a0975764b611448e3adeab287c7ff2df300bf42ef2' 
  AND token = 'fzsbVDGqnDV81l2vEdNt/mjwLu0cAElTAR5sYDM33zk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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