SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62cdbca4d0aab5cdcda46292c57ee41f82395fabb8d65a5273f0811f394612d2' 
  AND token = '5KgcNEPLd1IR/k7Ad5okDcwShAQ/1IDj4kOhn5jkvJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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