SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ff3ae0d9866f4f06b957a3b09811e0a0dd0bf3222fad78e95fa52581e4ea0c2' 
  AND token = 'SSNkCuCxETz4bx1qYjTmrbUiGgShxv/ct9bzduSWiB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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