SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cd816ff925b69e391943497e4da80aadd2f34416851f43ed7991e49ddee62e0' 
  AND token = 'kF8ZVRKbWKRqaS/s9kWAlInhneBwihIbadRKlkVNFOA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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