SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7831e13dca13085c1f55c1f95d87373c5a3fee3df0610f263feb3fe1ba437a1' 
  AND token = 'qQ1cY1sOwRGgFHDMWmkP0+IMmKE6xOSgP1mWgLYUq2U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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