SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '231ef245853a348c6ef4506927552ea4889be3bb2452818676f28a90caf2e2a6' 
  AND token = 'ejDijiFzbjuDuBMY7mkGxOQPMYyR/5M2otKYsfOhLdg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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