SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '518814d00c0937dc42220448d409e35da84d85b9914c9157523453ed1edf8ec6' 
  AND token = 'yurADcZr0/8wB+dEGuHsmoAAqYAUNhvvThdJlt3JsFw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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