SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b203fb2b27714ca7c6a74c649c2e0a23ec0ed9b54ebf0c83e6d1ad53cdd260e1' 
  AND token = '1kQvsN8dL/bYaN7kMXVBX6kOuu3TsMCvOsNS+KPLlko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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