SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a6f2723aabb00e8ab601ddeaf376537e4a473093676033056a71deee35eadf15' 
  AND token = 'GvK88FBtcX1wSllkDxGEoicJQNLci6obDei9skMnI+0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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