SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38104141b541e344d6685ded554dc9d809c733e2dfd8f833e5d2a4299bb856bd' 
  AND token = 'rz3zFhfgvvqtT7g+xOxBrRapBKZHRNKsCwVef+NTgM4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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