SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28d3dd6703d874f5babc183d0f602a7131f07f460b49016b99285e7741b0f111' 
  AND token = '4JLdxAP0aATutflGsea1i0n/qudt26YgqWylJCjQzAs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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