SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f0375c2540cc6880fe64bba55446f089b251dff423cf81126641a27e4931aee6' 
  AND token = 'QoxWDLzYJOOAGoImebMllLsb2drqWsnCVIGiUvCpCFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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