SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '1903458e0bd5209e2ebf91210267ae775ea6f49f3c9584ae4b0799a561af6811' 
  AND token = 'U9ln9TTBbaKIL+2otjncNyQuBzsv/J2BZQ1jn/OZI5I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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