SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c52427e4c760eab7cfa36c98e3c51f900afbc4888d4643f77a894d12f33783c' 
  AND token = 'Co8rw+LFRGV4P5S+h8JJgLtz6YmrYkR677n4u2KXgvI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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