SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f873a5753788cd8b5a274cdaa250c4fa4cb3643c6e29c9350c7a59cf68ba8b0c' 
  AND token = 'YMpTvaftI2k7gWwa7zlbqB5pK3LG+4BI5lK65KLXbZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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