SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a1db65c9fd472e05d3d378a67d2a0bddc15ef0eb35d193a631b97dcccc86e6f4' 
  AND token = 'B+3PjzhOmNgIP2jElzsl/LgqlmnwSlKMSEh6PeYj9oc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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