SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fab9aa8fc21716efe95903a6909c58f324e340ee2ebba55fffbb550507858aba' 
  AND token = 'lyykgU9XVqlF9Wa73X2LTJn13SyI7pifnR5UAzM28jE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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