SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fefd7516b1a72a18d0e09aafe80947f9c8b185e87fe7af7cc187566f3877b9d1' 
  AND token = 'IOQptRuABTQXoi8+1IChTdjd0EDR50i1TTL2OyMaaVI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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