SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '71c21cc9ca3b5a01add79a61dac9bafc084b827dcf565b51d97bc573300664c5' 
  AND token = 'kF3Ntd+4SCnnp322DS4MagwBCimdpWzM9c0gkF0Q5mc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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