SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5f4f4f1c8ea5cbc82466d66322a9987978417ed0ceb3da188c31d6056259442a' 
  AND token = 'lx7iEUqbAYPQHXLWPPHP3DH+BlJyAFOHyrajBsRv0gg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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