SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b932fcae1beff8ea40899867a5cf22a44c81a44ba42f9839b31d8389ab903a1b' 
  AND token = 'rtEkb696hP1WpaiLltFdzAfKpyisbXYBx9tHxS03614=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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