SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca99d1482808db971b80fbe8797f65b139bfdd9fb85cc18ca783fc74881dc796' 
  AND token = 'qMHhDbQ5sZjrt5T6UQFy2koi+b7pZdmejzwkXESrtHI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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