SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b36d83088178b50f36db8303063916b5fa0bbfe6e47796be1b0eb143c8d4d799' 
  AND token = 'FCRF9++LeKg1QO8MTB4ntcSLkAnjdyJwExxBtPEC1PY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00075

JSON explain

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