SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23450a32bbc5d305460ec3af244c468197970ee5ded5b862159ec37c95ec8368' 
  AND token = 'JtXRcl15FjLfMBVgHW6ewMOtqloCINhDiVHFu+vQ1FM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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