SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3064ebcbaa1b007ed9a33c467a927fdb312a527d2f09861c5e49cb8efacc8849' 
  AND token = 'W7C5YoxWO7abx99sowvklUBsm+MgbSfT6B8PXn2jFBk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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