SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b0ecacee12cfd19307b8c0c42c96799fc47a2e83482f7ef0915eb99eba172cd' 
  AND token = 'kusWQn/OyA4a7ytKne9tLOJo8n0g4y5j53o4f8+qh20=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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