SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b192eb2c827de634b6ac9a4e91b00d0797871c89c265136de001c52ac623ee3' 
  AND token = 'FAFu9xFeYl+97Veu6aJWLDbjddODt2dXZXi8BGus5Lg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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