SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a97d647af1f8289877f750bf64242a1f78efb4ab9be2687e99cbff121b580bd1' 
  AND token = '45l1vFxkM3LUDdIaMPcatf6enO+oVLeI1Lwd4yhqZv4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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