SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '946519c993f87272f819158f363a054a711b7fec38dd018cf68d1252048a410c' 
  AND token = 'UnH+js2xSFHhfeyMKEXPyIlwNjdAewTFSvKsXMesprY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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