SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89c47cc9c5da10c55a3a2eadebd59fa32d70f4be793d6249111b89f2e9d1e103' 
  AND token = 'LuC2TZHwXPQ1ZDHcp2zf2/sqZsWSytzfLLdco9dUy4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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