SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3e7be373a3639407952fa6558af40017ecaad07cba59807dede1fcd2ba48469' 
  AND token = 'LFqr+SK44W/xeHPxr8VR4vRpPBGBIzjIO79Ci3VCYas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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