SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9eeec4215ed1ed3444c32d1827ca6a95739bac21a1e1afb95804512011c27fba' 
  AND token = 'POpQCwLk8U5F/RlCr8LHbWCRGvLI558gkpKSPj7QHdY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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