SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55a17807f63f4bbfd1487ed0e66952eceaad5820fc75d14e126c5caf16898fb9' 
  AND token = 'M/lVfAE1YCI+RIdehuXBxlhJXdvew4zmQjMPj2VGKVs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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