SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '905d8b90ae258f27abc19c47c9cf9c00a6cbb36695086ad4da9f2ef0c672d344' 
  AND token = 'bld5bM9JMB6RRyDookBa0Sr0hjRQ8YfsrBbP80rSEQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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