SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff54bd3cb68903162f08b1bdcfca50633e4b3c0ac87cb95f3c190787c6c1df54' 
  AND token = 'mlT9XE5ojHYqHX+oaRwM/mZw4PT7DNgHGjKLVNfMS9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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