SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31964d4df0651382fa49d38b922ec2888c1bf1de7654f180f3e8ad4f56d251e2' 
  AND token = 'gN8bbiGX/RJNBwwaiHlzyKKbqL4q/IeYr6g3kSYgvNM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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