SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5968ea8fabf23fff59d7c44f638f9789b641395a3d989f63445411e0b5635f2' 
  AND token = 'IbauU4ddS81xLKE/1qHyX6eNIQGjZk0xLB2lHEdauBI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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