SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '373d9929d04bf76be5a543f4c8a240db905be8b5e0ed521432464100728f1671' 
  AND token = 'z8mxE1SGtAGdy16ywCj1ipWexfeTG1Bq55FNn68AHh4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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