SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9d6c573b63fcd0c47da610f062b5de0ecd42d92ada9381eb6c550ddbc521844' 
  AND token = 'p/Wxi5sjgL63/4WcPJzboj2LsH0oUBzxbIFEZHDnfzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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