SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b433e74440f6e9feefea0dbfc48802d78cb5c5833fb7d80bfee72688b243e31a' 
  AND token = 'D+6bSLT3gx/oPzF/HCKjyfwivGFodRBV1L67QyztvPU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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