SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ffca50d0145603842a687bac846cccfb691f2d8f3dbf51999f57c6968c2d0feb' 
  AND token = 'XqIriWwhOB1ZvSyrWjbmPViOMOOQva1675+geEsjd6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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