SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fecfc788ccefc1f329958e9048dda1b41300e73d151bf4a07892efbacecdf250' 
  AND token = 'vozBLowV3uf36PNyeG93/iPB2l/uwMgxIL4yCmA6PZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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