SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef10dc334819982ef845e3f14e63aea0f308f18f0e63037c5817a8bea704dc1f' 
  AND token = 'MLCPZIDHteTZdEFzyOY6ebQpZFSYCah6DW4XCJmhuKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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