SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1065d8581af0324f271f6c66d15674a649964428319b329c82b77a1fbc4059f4' 
  AND token = 'FiWaHwRZWHB1kiNDfDZIrJppxMzLMua2SYsYws4xcr4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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