SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '825c87a308f9076b2664992390f6607904cc0346e9bf66885ba4aa4474ca138c' 
  AND token = 'OWxjPizKVm1kzC7QkXpBRRGNI334d7AL26+J18hwIqg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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