SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35937524d3f30d03f0278eb6f781054bf2fd43f6b35aa920dd652478c496f7e0' 
  AND token = 'SyzXVPasN5gSUHF+x2RDjDyu4y64KubrdVS/PBNqRtA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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