SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6b9aeb3494627b551ea967859f2e2b2194b0474a1993ce0fab75981bc058140' 
  AND token = '/58+NPQE6q6WVYca74MNONcyzsa3VUHC4Y2KLLkdzCU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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