SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b679c1dc423d557cb3783e442c1ebc1b922f177ef3f226a8be5e7d00cf94b7d0' 
  AND token = 'HuP1qVzgN4BDyf+ChMLumt8M/ZsS1JfCYtAVHbXe+lY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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